POLYKETONE POLYMER COMPOSITION

Abstract: Cross-linkable and cross-linked compositions comprising a major amount of polyketone polymer and a minor amount of an iodide salt. Compositions containing a iodide salt which is an onium iodide salt of nitrogen, phosphorus, arsenic, or a combination thereof of which the cation coordination sphere is shielded by aromatic substituents, or an alkali metal iodide, show improved oxidative stability. Further, the invention relates to a process for preparing such compositions and to a process for cross-linking such compositions.

Description: POLYKETONE POLYMER COMPOSITION The present invention relates to polyketone polymer compositions. Polyketone polymers exhibit many desirable physical properties which make them suitable for engineering thermoplastic applications. In particular, high molecular weight linear alternating polyketone polymers possess such properties as high strength, rigidity, toughness, chemical resistance, and wear properties. While these properties are adequate for many applications it would be of advantage to further improve certain properties such as environmental stress crack resistance, chemical resistance, creep resistance, increased use temperature and increased tensile strength. One method known in the art for providing these improvements has involved the cross-linking of linear polymer chains of a thermoplastic polymer. .An example of this is polyethylene which can be made to exhibit increased durability, use temperature and strength through post-reactor cross-linking. In order to maintain good melt processability and flow during part fabrication it is generally desirable to utilize polymers of substantially linear molecular structure before cross-linking. Therefore, it is particularly desirable to have a simple procedure which can cross-link the substantially linear polymer after melt processing. Cross-linking a polymer after melt processing is useful in maintaining a high degree of crystallinity in the final part and allows common methods of melt fabrication such as injection moulding, extrusion, and blow moulding to be used. The present invention relates to a composition comprising a major amount of polyketone polymer and a minor amount of a iodide salt with the proviso that the composition is not a composition containing 5.0 parts per million by weight of sodium iodide, metal content on polymer. It has been found that such composition can be cross-linked to give a composition having and exhibiting improved mechanical and chemical resistant properties. Further, the present invention relates to blends containing such composi'tion. The polyketone polymers which are useful in the practice of the invention are of a linear alternating structure and contain substantially one molecule of carbon monoxide for each molecule of ethylenically unsaturated hydrocarbon. The preferred polyketone polymers are copolymers of carbon monoxide and ethylene or terpolymers of carbon monoxide, ethylene and a second ethylenically unsaturated hydrocarbon of at least 3 carbon atoms, particularly an oc-olefin such as propylene. When the preferred polyketone terpolymers are employed as the major polymeric component of the blends of the invention, there will be within the terpolymer at least 2 units incorporating a moiety of ethylene for each unit incorporating a moiety of the second hydrocarbon. Preferably, there will be from 10 units to 100 units incorporating a moiety of the second hydrocarbon. The polymer chain of the preferred polyketone polymers is therefore represented by the repeating formula -[—CO—(—CH 2 —CH 2 —)-] χ —[CO—(-G)—]~y where G is the moiety of ethylenically unsaturated hydrocarbon of at least 3 carbon atoms polymerized through the ethylenic unsaturation and the ratio of y:x is no more than 0.5. When copolymers of carbon monoxide and ethylene are employed in the compositions of the invention, there will be no second hydrocarbon present and the copolymers are represented by the above formula wherein y is zero. When y is other than zero, i.e. terpolymers are employed, the —CO- (-CH2-H2-)- units and the —CO-(G-)- units are found randomly throughout the polymer chain, and preferred ratios of y:x are from 0.01 to 0.1. The precise nature of the end groups does not appear to influence the properties of the polymer to any considerable extent so that the polymers are fairly represented by the formula for the polymer chains as depicted above. Of particular interest are the polyketone polymers of number average molecular weight from 1000 to 200,000, particularly those of number average molecular weight from 20,000 to 90,000 as determined by gel permeation chromatography. The physical properties of the polymer will depend in part upon the molecular weight, whether the polymer is a copolymer or a terpolymer, and in the case of terpolymers the nature of the proportion of the second hydrocarbon present. Typical melting points for the polymers are from 175°C to 300°C, more typically from 210°C to 270°C. Preferably, the polymers have a limiting viscosity number (LVN) , measured in m-cresol at 60°C in a standard capillary viscosity measuring device, from 0.5 dl/g to 10 dl/g, more preferably from 0.8 dl/g to 4 dl/g. A preferred method for the production of the polyketone polymers has been described in EP-A-181014, EP-A-248483, EP-A-600554, EP-A-314309 and EP-A-391579. The useful iodide salts are those which are capable of cross- linking polyketone polymers under appropriate conditions. Examples of these salts include those listed in Table 1. Linear polyketone polymers containing a sufficient (minor) amount of iodide salt can be cross-linked by subjecting the composition to the presence of oxygen at elevated temperature. While not wanting to be held to any particular theory, it is believed that some oxidation of the polyketone polymer occurs which in the presence of a iodide salt catalyzes the cross-linking reaction. The extent of cross-linking is controllable by the amount of exposure to heat and oxygen. The time required to obtain a desired level of cross-linking is inversely related to the temperature used or the oxygen content available. An effective oxygen source is air. The amount of heat required is that which is sufficient to lead to the cross-linking of the polymer. The required amount of heat can be obtained at a preferred operating temperature of about 70°C. While the inventive process can cross- link a polyketone polymer melt in the presence of sufficient oxygen, it is generally preferred to cross-link at temperatures below the crystalline melting point of the polymer. Methods known in the art for cross-linking polyethylene include (1) the use of high energy radiation, (2) thermochemical reactions, and (3) moisture induced reactions. Methods (1) and (2) rely on the initiation of free-radical intermediates either through radiation or radical initiators such as organic peroxides. In polyethylene these radical intermediates result in chemical cross-links between polymer chains; however, these methods are not applicable to all polyolefins. Polypropylene and polybutylene are examples where radical initiation does not result in cross-linking, but rather chain scission. These methods also possess certain disadvantages which are known to the skilled artisan. The method of cross-linking polyethylene which utilizes moisture first requires free-radical grafting of vinyl silane units onto the polyolefin which are then capable of reacting with water to produce chemical cross-links. Since cross-linking occurs after melt processing, this method like radiation curing, allows conventional fabrication methods to be used and maintains a high degree of crystallinity after cross-linking. The above methods are not entirely suitable for polyketone polymers. Radiation curing is not possible because chain scission reactions can occur in polyketones. Thermochemical cross-linking processes which involve adding enough heat to cause the substantially linear polymer to melt and flow into a desired form just as cross-linking occurs are also not suitable. First, the processing temperatures of polyketones are considerably higher than in polyethylene which would result in the premature decomposition of any free-radical initiators (organic peroxides) . Second, unlike simple polyolefins, the reactivity of polyketones is more diverse and can lead to unwanted free radical degradation reactions of the polymer. Moisture cross-linking of polyketone polymer may be possible if silane grafting could be carried out by some means other than a free-radical process. It is envisioned that a silane grafting method for polyketones is feasible if the vinyl groups commonly used in polyethylene were replaced with groups capable of reacting with ketones such as amines. Examples would include (trialkylsilyl)- alkylamines and (trialkylsilyl)aryl-amines. The current invention takes a linear polymer which is completely soluble in HFIPA (hexafluoroisopropanol) and cross-links it such that it becomes only swollen by the solvent. r One method known for determining the extent of cross-linking is by measuring its solubility or swellability in a suitable solvent. Suitable solvents are usually polar solvents with low molar volume, especially those having a strong hydrogen bonding characteristic. Examples of such solvents include hexafluoro-isopropanol, m-cresol, and phenol. Hexafluoroisopropanol is preferred because of its ability to dissolve the polyketone polymer at room temperature. Furthermore, it has surprisingly been found that compositions containing certain iodide salts, show improved oxidative stability. A disadvantage of linear alternating polymers of carbon monoxide and at least one ethylenically unsaturated hydrocarbon is that they can exhibit a deterioration of physical properties upon thermal oxidative degradation. This degradation is due to a chemical attack of atmospheric oxygen on the polymer chains and is characteristic of most, if not all organic polymers. Oxidation is typically autocatalytic and occurs as a function of heat and oxygen, hence the term thermal oxidative degradation. It is desirable to inhibit the deterioration of polymer properties by stabilizing the polymer toward the adverse effects of heat and oxygen. There are a large number of thermal oxidative stabilizers which are employed commercially to stabilize thermoplastic polymers against such degradation. However, many of the thermal stabilizers which are known to be effective with polyolefins, polyamides, polyacetals, polyacrylates, etc. are only marginally or not at all effective when employed with polyketone polymers. An oxidatively stabilized polyketone polymer composition has now been found. The composition comprises an onium iodide salt of nitrogen, phosphorus, arsenic, or combination thereof in which the cation coordination sphere is shielded by aromatic substituents or an alkali metal iodide, with the proviso that the composition is not a composition containing 5.0 ppmw of sodium iodide, metal content on polymer. In EP-A-600554 it has been described that the melt stability of polymers can be adversely affected by the presence of alkali (ne earth) metal salts. In experiment 1 has been described a composition containing 5.0 parts per million by weight of sodium iodide, metal content on polymer. The composition of the present invention can be prepared by contacting the polyketone polymer with the iodide salt. More specifically, the methods can comprise a) melt compounding after contacting the iodide salt with polyketone polymer by powder mixing or solvent deposition, b) diffusion of the iodide salt into polymer articles by treating the polymer with a solution containing the iodide salt, preferably using a solvent which has some miscibility with both polymer and the iodide salt, or c) in- situ generation of the iodide salt utilizing a polymer blend comprising of precursors which upon application of a sufficient amount of heat generates the iodide salt. Preferably, the iodide salt is introduced by diffusion. Thermal oxidative degradation of organic polymers relates to the deterioration of polymer properties due to the chemical reaction(s) between the polymer and atmospheric oxygen. While oxidation processes are complicated and mechanistic pathways of oxidation between different polymers may vary, oxidation is generally promoted by heat, often initiated by trace impurities such as metal ions or organic prodegradants, and characterized overall as autocatalytic in which carbon radicals and peroxyl radicals constitute key intermediates in the catalytic cycles. Consumption of oxygen by the polymer propagates the catalytic cycle and generates oxygenated species which either comprise part of the polymer or are evolved as gaseous products. These oxygenated species may further be prodegradative to the polymer. For example, hydroperoxides are not inherently stable and are capable of decomposing into new radicals, either thermally or catalyzed by trace impurities, which can then initiate additional oxidative cycles. For polyketones it is believed that the thermal oxidative process involves the formation of oxygenates which under aging conditions cleave polymer chains and result in a reduction of molecular weight and a loss of polymer entanglement. Ultimately this results in a deterioration of polymer mechanical properties such as reduced impact strength, loss of elongation at break, and embrittlement. It would therefore be advantageous to stabilize the polyketone polymers towards these property losses either by reducing their overall rate of oxidation or reducing their rate of polymer chain scission. The iodide salts which are especially useful in thermal oxidative stabilization, have been described in Table 1. TABLE 1 TABLE 1 (Cont ' d) 5-methyl-3- (methylthio)-1,4-diphenyl 1H-1,2,4- PPh 3 MeI - Methyltri- triazolium phenylphosphonium iodide 9-phenanthryl triphenylphosphonium PMe(OPh) 3 I - Methyltri- phenoxyphosphonium idodide PPh 4 Cl - Tetraphenyl- phosphoniu chloride KI (diffusion only) PPh 4 Br - Tetraphenyl- phosphonium bromide 1 Other alkali metal iodide salts such as lithium, potassium and sodium iodide are also within the scope of the invention. The iodide salts will generally be present in an amount within the range of from 0.0001 to 10, more specifically 0.001 to 10 percent based on the weight of the polyketone polymer, preferably in the range of from 0.1 to 1.0 percent based on the weight of polyketone polymer. Further, it was found that an improved oven aging performance of the polymer is obtained if not only the iodide salt is present, but also a hindered phenol, more specifically a composition, wherein the hindered phenol is benzene propanoic acid, 3,5-bis (1,1-dimethylethyl)-4-hydroxy octadecyl ester and/or benzenepropanoic acid 3,5-bis (1, 1-dimethylethyl)-4-hydroxy-l,2- ethanedyl bis (oxy-2,1-ethanediyl)ester. After preparation, the now stabilized polyketone polymers show improved retention of desired mechanical properties, such as resistance to embrittlement when tested under conditions of elevated temperature and air exposure. The test as disclosed in U.S. Patent No. 4,994,511 subjects polymer samples to aerobic oven aging at various temperatures and monitors the time until brittle failure (cracking) occurs when sharply bent at an angle of 180°. The following examples and tables further illustrate the various aspects of the invention. EXAMPLES ON STABILIZATION Polymers used in the following examples are described in Table 2. An oven aging test was used throughout the examples to distinguish the performance of polymer additives. In this test, polymer sheet of 5.1 x 10~ 4 or 7.6 x 10~ 4 m (20 or 30 mil) thicknesses was prepared either by melt extrusion or compression moulding. Test specimens were then cut into 1 cm wide strips and placed into forced air circulating ovens at 100 °C or 125 °C. Periodically, the strips were withdrawn from the oven and when cooled bent to a 180-degree angle. When the samples became sufficiently brittle to break under this test procedure it was considered to be a failure and the time to embrittlement was recorded. Table 2. Polyketone polymers used in illustrative examples. LVN Tm Base Polymer dl/g °C Form Additives" A 1.95 220 Ext. Sheet 3 0.5% Irganox 1330 d 0.5% Nucrel 535 e B 1.86 220 Ext. Sheet 3 0.2% Irganox 1330 d 0.2% CaHAp c 0.3% Nucrel 535 e C 1.77 220 Powder 0.2% Irganox 1330 d 0.2% CaHAp 0.3% Nucrel 535 e D 1.73 220 Powder 0.2% Irganox 1330 d 0.2% CaHAp 0.3% Nucrel .535 e E 1.87 220 Powder None a Extruded sheet of 5.1 x 10 -4 m (20 mil) thickness. ^Percent based on weight of polyketone polymer. c Calcium Hydroxyapatite. d 4,4* ,4"-[ (2,4,6-trimethyl-l,3,5-benzenetriyl)tris- (methylene) Jtris [2,6-bis (1, 1-dimethylethyl)-phenol] e polymer of ethene with 2-methyl-2-propenoic acid. Examples 1-5 Examples 1-5 demonstrate the utility of iodide additives to heat aging when diffusionally incorporated into polyketone polymer. Test specimens were prepared by immersing polymer A in the form of 5.1 x 10 -4 m (20 mil) sheet into a water composition for 20-25 min at a temperature of 90-95C. The water used was HPLC grade, OmniSolv supplied by EM Science. Water compositions used in examples 2-5 included: water alone, 0.30 wt% Znl 2 , 2.0% KI, and saturated Ph PI which is only sparingly soluble in water at 90-95 C C. After exposure, the polymer specimens were cooled, wiped clean of any surface residue, and dried in a vacuum oven at 50 C C with a nitrogen purge over night. One centimetre wide oven test strips were then cut from the exposed sheets. For the sample which was exposed to Ph 4 PI, neutron activation tests were conducted to determine the iodide present in the polymer after this exposure. Residual iodine measured ca. 900 ppm, calculating to 0.33% Ph PI present in this sample. Results of oven aging tests are shown in Table 3. TABLE 3. Iodide additives diffusionally incorporated into polyketone polymer. . Examples 2 and 3 show that simply exposing the polymer sheet to water alone or to a solution of Znl 2 does not result in improved heat stability. Exposure to KI and Ph 4 PI results in an improvement in heat stability with Ph PI being far superior in its ability to stabilize this polyketone polymer - greater than 2 times the control, Example 1. Examples 6-10. Test specimens used in Examples 6-10 were diffusionally prepared and then tested as described in Examples 2-5 using polymer A and water compositions which contained 2.0% of the corresponding test additive. The results are summarized in Table 4. i.Δ TABLE 4. Onium iodide salt additives diffusionally* incorporated into polyketone polymer. Examples 7, 8, & 10 show that of the Ph P halide salts only the iodide is stabilizing to polyketone polymers. Example 9 demonstrates that alkyl ammonium iodides such as tetraethyl- ammonium iodide (Et 4 NI) are not effective in stabilizing polyketone polymers. This demonstrates that not all onium iodide salts are effective as stabilizers for polyketone polymer. Examples 11-13. Examples 11-13 were prepared as described in Example 1-5 with the exception that extruded sheet of polymer B was used instead of polymer A. Test specimens for examples 12 & 13 were prepared similar to Examples 7-10. Oven aging results are shown in Table 5. TABLE 5. Comparison of iodide salts diffusionally added to polyketone polymer. These examples show once again that not all iodide salts are stabilizing to polyketone polymer. Calcium iodide shows no improvement in time to embrittlement over the control. Examples 14 - 16. Examples 14-16 demonstrate that powder mixing of Ph PI and polyketone polymer followed by melt processing results in a polymer composition with improved thermal oxidative stability. Examples 15 and 16 were prepared by combining 100 grams polymer C powder with Ph PI powder and then homogenizing by tumbling overnight. Each mixture was then extruded on a 15 mm Baker- Perkins twin screw extruder operating at a melt temperature of about 250 °C. The extruded compositions were then used to make plaques of 30 mil thicknesses by compression moulding. As shown in Table 6, compositions with Ph 4 PI showed significantly improved time to embrittlement at 125 °C over the control. TABLE 6. Aging performance of Ph PI melt blended into polyketone polymer. Examples 17 - 26. Examples 17-26 compositions were prepared by melt processing as described in Examples 14-16 with the exception that polymer D was used instead of polymer C. Oven aging test results shown in Table 7, illustrate that onium iodide salts with alkyl substituents (ex. 18-22) exhibit no stabilizing influence on polyketone polymers. Examples 25 and 26 demonstrate the stabilizing influence of iodide salts other than Ph 4 PI which also contain onium cations shielded by aromatic substituents, i.e. bis (triphenylphosphoranylidene)ammonium and a triazolium salt, respectively. In these examples, the increased stability was somewhat small, but similar in magnitude to the benefit from Ph 4 PI in this polymer, Example 24. Table 7. Aging performance of onium iodide salts melt blended into polyketone polymer. a bis (triphenylphosphoranylidene)ammonium iodide b 5-Methyl-3-(methylthio)-1,4-diphenyl-lH-l,2, 4-triazolium iodide Examples 27-39. Examples 27-39 compositions were prepared by melt processing as described in Examples 14-16 using the polymers and additives identified in Table 8. Example 30 demonstrates the improved resistance to embrittlement using only PPh 4 I. Example 31 shows a significant improvement when a commercial hindered phenolic antioxidant such as Irganox 1076 is combined with Ph PI in polyketone polymers. This combination results in improved oven aging performance compared to using either individually. Examples 33-39 demonstrate that in-situ formation of phosphonium iodides from a phosphine and an organic iodide components improves the stability of polyketone polymer just as effectively as using Ph PI. Examples 34-37 show that the use of either triphenyl phosphine or 1,4-diiodobenzene alone do not contribute to the stability of polyketone polymers. However, the combination of these additives in Example 33 yields a polymer with significantly improved heat aging performance. Examples 38 and 39, further show the beneficial effect when an organic iodide and triphenyl- phosphine are combined in the additive package. TABLE 8. Aging performance of phosphonium iodides melt blended into polyketone polymers and generated in-situ. a n-octadecyl 3- (3,5-di-tert-butyl-4-hydroxyphenyl)propionate b 3,5-bis (1,1-dimethylethyl)-4-hydroxy-l,2-ethanediylbis (oxy-2,1- ethanediyl)benzene propanoic acid ester. EXAMPLES ON CROSS-LINKING Example 1 Polyketone polymer A with a melting point of about 220 °C and limiting viscosity number of 1.87 dl/g was compounded with 0.3 wt% tetraphenylphosphonium iodide (PPh 4 I) and 0.5% Irganox 1076 on a 15 mm Baker Perkins extruder operated at a melt temperature of approximately 250 β C. A control was prepared by extruding polymer A as described above without the use of any additives. After this, the pellets were dried in a vacuum oven at 50 C C under nitrogen and then compression moulded into 5.1 x 10 -4 m (20 mil) thick plaques. Test specimens were cut from the plaques in 1 cm wide strips and exposed to oxygen and heat using a Blue M forced air oven set at 125 °C. The samples were withdrawn from the oven after 11 days exposure and submitted for GPC analysis using hexafluoroisopropanol (HFIPA) as solvent. GPC analysis utilized ZORBAX 1000 and 60 PSM columns in series and a Waters 410 differential refractometer as detector. Table 1 shows that as expected of linear polyketone polymers, both unexposed samples were completely soluble in HFIPA. After exposure to heat and oxygen, polyketone polymers without iodide additives are soluble and exhibited a molecular weight loss. The polymer sample containing iodide became a swollen gel (50% sol) indicative of a cross-linked polymer. This sample, however, did not experience embrittlement in the same oven until 43 days compared to the specimen without PPh I which embrittled in only 15 days. Table 2. PPh 4 I Promoted Cross-linking of Polyketone Polymer Molecular PPh I Days @ Weight Content 125C (Mn) None 0 55900 None 11 34510 0.3% 0 55280 0.3% 11 Insoluble Example 2 Polyketone polymer B, with a melting point of about 220C, an LVN of 1.95 dl/g, and containing 0.5% Irganox 1330 and 0.5% Nucrel 535, was melt extruded into 5.1 x 10 -4 m (20 mil) sheet. One centimetre wide strips of this sheet were exposed to heat and oxygen as described in Example 1. In addition to these strips, a separate set of strips was submitted to a saturated aqueous PPh 4 I solution at 85 °C for 20 min. The strips were removed, wiped clean, and then dried in a vacuum oven at 50 °C under nitrogen purge. These strips containing PPh 4 I by diffusion were then exposed to heat and oxygen as described above. Table 2 shows that after heat exposure the polyketone polymer with iodide was again an insoluble swollen gel (20% sol) in HFIPA, while the sample without iodide treatment was completely soluble and displayed a loss in molecular weight. This example shows that iodide can be added after part fabrication but before heat and oxygen is applied to yield a cross-linked polyketone. Table 3. Diffusional Treatment of Polyketone Parts with PPh 4 I Molecular Weight PPh I Treatment Days @ 125C (Mn) No 0 50562 No 5 34660 Yes 5 Insoluble Example 3 Polymer strips containing either potassium iodide or tetraethylammonium iodide were prepared and tested as described in Example 2 with the exception that 2 wt% of the respect iodide solutions were replaced for the PPh 4 I solution. It was observed that after 10 days at 125 °C both samples were insoluble in HFIPA. This demonstrates that iodides other than PPh 4 I also promote oxidative curing of polyketones. Example 4 Polyketone polymer C, melting point of about 220C and LVN of 1.84 dl/g, was injection moulded into 1/8 inch ASTM D-638 tensile bars. Part of the bars were exposed to heat and oxygen for 20 days as describe in Example 1, while a separate set was first treated with a saturated aqueous solution of PPh 4 I at 80 °C for 90 minutes before heat exposure. Table 3 shows the tensile property, GPC, and DSC results before and after heat exposure. GPC was measured both on the skin and core of the tensile bars, while DSC was measured on the skin. This example shows that PPh I promotes oxidative cross- linking which provides greater tensile strength and solvent resistance while maintaining a high degree of crystallinity. This example demonstrates that PPh 4 I promotes oxidative cross- linking which provides greater tensile strength and solvent resistance while maintaining a high degree of crystallinity. Cross- linking, as indicated by insolubility in HFIPA, is demonstrated only in the sample containing PPh 4 I combined with sufficient exposure to heat and oxygen, i.e. the outer portions of the sample. As a result of cross-linking, the PPh I-containmg sample shows a 24% increase in yield strength, while the specimen without PPh I exhibits oxidative degradation resulting in a loss of yield and molecular weight (40% drop in number average molecular weight (Mn) of skin) . Cross-linking in the manner described did not diminish the extent of crystallinity relative to the uncross-linked polymer as apparent in the large heat of fusion values which are a proportional measure to the extent of crystallinity. Table 4. Diffusional Treatment of Polyketone Parts with PPh 4 I. Days Yield Break Heat PPh 4 I β Strength, Strain Mn Tm, Fusion, Treated 125 °C psi % Mn (skin) (core) °C J/g No 0 8700 670 46825 222 81 No 20 No yield 9 23 28163 52305 222 103 Yes 0 8700 670 46825 Yes 20 10790 70 Insoluble 53482 219 100 o i Break stress was 9180 psi .

Claims: C L A I M S 1. Composition comprising a major amount of polyketone polymer and a minor amount of a iodide salt with the proviso that the composition is not a composition containing 5.0 parts per million by weight of sodium iodide, metal content on polymer. 2. Composition according to claim 1, in which the polyketone polymer is a linear alternating polyketone polymer. 3. Composition according to claim 1 and/or 2, in which the iodide salt is an onium iodide salt of nitrogen, phosphorus, arsenic or a combination thereof, in which the cation coordination sphere is shielded by aromatic substituents, or an alkali metal iodide. 4. Composition according to claim 3, in which the iodide salt is selected from the group of tetraphenylphosphonium, 5-methyl-3- (methylthio)-1,4-diphenyl 1H-1,2,4 triazplium, bis (triphenylphos- phoranylidene)ammonium, 4-iodophenyltriphenylphosphonium, 1,4- bis (triphenylphosphonium)benzene and 9-phenanthryl triphenyl- phosphonium. 5. Composition according to claim 4, in which the iodide salt is tetraphenylphosphonium iodide. 6. Composition according to any one of claims 3-5, which composition further comprises a hindered phenol. 7. Composition according to claim 6, wherein the hindered phenol is benzene propanoic acid 3,5-bis (1, 1-dimethylethyl)-4-hydroxy octadecyl ester and/or benzenepropanoic acid 3, 5-bis (1, 1-dimethyl¬ ethyl)-4-hydroxy-l,2-ethanediyl bis (oxy-2, 1-ethanediylJester. 8. Composition according to any one of claims 1-7, wherein the iodide salt is present in an amount of from 0.0001 to 10 wt%. 9. Composition according to any one of claims 1-8, which composition has been cross-linked. 10. Process for preparing a composition, which process comprises contacting a polyketone polymer with a iodide salt with the proviso that the iodide salt is not sodium iodide. 11. Process for preparing a composition according to claim 9, which process comprises treating the polyketone polymer with a solution containing the iodide salt. 12. Process for cross-linking a coπposition as described in any one of claims 1-8, which process comprises subjecting the composition to the presence of oxygen at elevated temperature. 13. Blend comprising a composition according to any one of claims 1-9.

Inventors: ASH CARLTON EDWIN, ASH, CARLTON, EDWIN
Applicants: SHELL INT RESEARCH, SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ B.V.
Application year: 1994
Main classification: C08K5
IPC codes: C08K5, C08L73